AllMovie

As season three of disaster master Irwin Allen's popular science fiction adventure series Voyage to the Bottom of the Sea gets underway, the crew of the SSRN Seaview is forced to do battle with a gigantic alien brain bent on world domination. Communications have blacked out over a thousand-mile stretch, and Captain Crane (David Hedison)'s crew has been charged with discovering the root cause of the massive malfunction. Upon locating a large alien brain deep beneath the ocean surface, the Seaview crew brings the anomaly aboard for closer inspection. When the alien brain takes over visiting scientist Dr. Lindsay it becomes an obvious threat to the crew, but when it targets Captain Crane it quickly becomes apparent that this is only the first step in a much larger takeover.